Conventionally, when a user uses a cash card or credit card issued by a bank, credit company, or the like at a store where a card terminal that accepts the card has been installed, the clerk at the store makes the card terminal read the card number stored on the magnetic stripe of the card and enters the transaction amount.
At this time, the card terminal connects to a communication line and sends information such as the card number and transaction amount to the management computer at the bank or credit company. The management computer at the bank or credit company manages such information as whether the card has been expired, whether the credit limit has been reached, and whether the card has been reported lost, and determines whether the card can be used, based on the card-number and payment-amount information received from the card terminal via the communication line. If it is determined that the card can be used, the management computer at the bank or credit company returns usage permission information to the sender card terminal while performing a procedure for debiting the transaction amount from the specified account of the card.
There is a problem with a system that employs such cash cards or credit cards: each time the user uses his/her card, the card terminal must send a request for approval to use the card to the management computer at the bank or credit company, creating a need to connect to a communication line and thus complicating the processing of card transactions.
If a user wants to use an installment payment plan via credit card, he/she makes an arrangement for direct debit with the credit company and the credit company automatically debits the fixed amount decided by the arrangement from the user's account on a fixed day every month. Therefore, the user must decide the amount of each installment in advance and it is difficult for him/her to decide the amount freely when making each payment.